Flipping food in a pan is not only the sign of an accomplished cook but also an efficient way to turn the food. The key to this technique is confidence, if you are tentative there will not be enough momentum for the food to move easily.
First choose pans with curved sloping sides, since that provides the proper angle for the food to return to the pan-- if you have a nonstick pan all the better.
First swirl the items in the pan, like this vegetable medley, to make sure that they are not sticking. Then push the pan away from you so the vegetables are pushed into the curved edge, if done with enough force, this sends the vegetables up in the air. Then pull the pan back to catch the vegetables, as they fall into the pan. It is a circular motion with the hand pressing forward and pulling back. The advantage of this technique is the food turns over evenly, which if you did it with a spoon they would not.
To get the hang of this action, try practicing it with a cool pan and dried beans.
When you get comfortable with a mixture, you might then want to step up to an item like this potato cake. The technique is the same, but here you add a little trajectory, so the item can flip in the air without hitting the side of the pan.
With this technique practice makes perfect, and don't worry if a little food flies out of the pan.

Instructor: Robert Bleifer